Propeller



P 1927' J. A. BLONDIN PROPELIILER Filed March 17, 1925 I N VEN TOR. Joseah .B/ONGII? 'JKWWW A TTORNE Y.

' metal Patented Sept. 2%, i927,

l d ilhd JOSEPH A. BLONDIN, Q1? L03 ANGELES, CALIEFORNM.

PROPELLER.

Application filed March 1'7, 1925 My invention relates to propellers andthe method or process for producing the same, said propellers beingadapted for use in connection with air or water craft, and also may beused in connection with any motive power associated with a blower orfan.

So far as I am aware. all previous metal lic propellers have either beenproduced from castings. necessitating complicated and intricate molds,or they have been composed of metallic blades secured to arms, or to a.separate hub section. In other cases said propellers have been composedof sheet faces welded together to simulate more or less closely thecontour and pitch of the conventional wooden propeller.

Another form out previously known metallic propellers comprises acontinuous piece of relatively thick plate, formed from a single blank,and havingtlat blades twisted to form approximately a helical or truescrew curve from the hub to the tip of the blade, said blades extendingin diametrically opposite directions from each other, so that theirattacking edges extend along lines which are tangent to the periphery ofthe hub section or flanges of the propeller.

As will be obvious, propellers produced in the above ways havenumerousdisadvantages, one of the main ones being the excessive cost ofconstruction. Moreover, propellers constructed as heretofore suggestedhave inherent Weaknesses which limit their life materially, due in agreat measure to the enormous stresses and strains resulting from thecentrifugal action caused by the rapidity of their rotation. It may alsobe stated that the specific manner in which said propellers areconstructed not only insures their rapid disintegration, as has beenclearly demonstrated in practice, but reduces their eiiiciency to amarked extent.

It accordingly is an object of my invention to eliminate eli'ectivelyall the above disadvantages and avoid all costly processes or methods,such as casting, molding, or other "foundry or machine methodsheretofore used in the production of propellers or fan blades of anysort.

Another object of my invention is to provide a novel form of propellerof the straight pitch type, the blades of which do not present anyhelical twist at their hub section, or at any extensions from said hubsection, thus eliminating the practically prohibitive Serial No. 16,108.

expense of providingspecial torsion producing or stamp and die machineryfor reflecting such a helical twist A further object of my invention isto provide a propeller the blades of which, from tip to tip. and alsoits central hub section, have the same arcuate curve, thus excluding;all sections which are fiat, and hence, by reason of said curve,overcome all tendency of the blades. while in operation. to "flex orbend backward or forward in the line of propulsion under fluid pressure.a fault oi? propeller blades commonly called flutter, which ischaracteristic oi all flat bladed propcllcrs.

A still further object oi my invention is to provide a novel form ofpropeller having; an improved hub construction which overcomes thefaults of propellers of the known type, said faults resulting- "fromclamping the propeller proper between flat-laced hub flanges, where onlythe friction oi said flanges against the propellerhub section cancooperate with the shear resistance of through-bolts.

More specifically, in my improved propellcr the hub section is otarcuate or cambered shape. the front and rear hub flanges havingcomplementary concave and convex surfaces. which, when clamped to thecambered hub section. not only cause the propeller to be driven throughthe bolts inst mentioned, and by reason oi the contact friction betweensaid surfaces: but in addition, and

mainly through the mass resistance of the propeller material itselfopposing by its cambered or arcuate surt'aces any possible independentturning or misalignment of the hub flanges, thus providing for a truelock between the propeller proper and the hub flanges.

Another object of my invention is to provide a novel form of metallicpropeller constructed out of a single continuous blank of vmaterial. orin its laminated type, of several such continuous blank units,superimposed, and held in mutual close contact by the clamping actionof. a special design set of hub flanges, together with any desiredfasteni'ng means, such as rivets or auxiliary bolts,

traversing said laminations at points exterior to said hub flanges.

It is also an object of my invention to provide a novel form ofpropeller which obviates entirely the use of special machine shop itsrill

ill;

Elli? Sill) tools, and the expensive processes or methods hereinbeforementioned, and which in use will withstand all centrifugal stresses,without distortion or warping of its blades, and

all thrust stresses, without bending or fluttering of said blades, andby reason of the thinness of said blades, and their shape, will reducepower consuming turning resistance to a minimum, and permit an efficientpropulsion with a minimum disturbance of the medium, such as air orwater, actedupon. A still further object of my invention is to provide anovel process or method of constructing propellers from sheet material.

Further objects and advantages of my invention will become more apparentas the description thereof proceeds.

Reference is had to the accompanying drawings in which similar referencecharacters denote similar parts. In the drawings, I

Fig.1 is a collection of perspective views illustrating the varioussteps involved in bringing about the construction and method ofproducing my improved propeller, I

Fig. 2 is a fragmentary plan view of the assembled laminated type of mypropeller, the arrows indicating the direction of rotation of saidpropeller,

Fig. 3 is a similar View showing; a propeller of the same type as thatof Fig. 2, but operated in a reverse direction as indicated by thearrows,

4c is a plan view of a conventional type of wood propeller,

Fig".- 5 is an end elevation of my improved propeller shown applied tothe shaft adapted to be driven thereby,

Fig. 6 is a cross sectional view on an enlarged scale through thelaminated propeller shown in Fig. 2, and

Fig. 7 is a view similar to Fig. 5, but positioned horizontally, andwith certain parts omitted for the sake of clearness.

Describing my invention more in detail, my improved method or process inproducing propellers constructed of sheet material, as shown in Fig. 1.consists in rolling a blank of sheet material A in tubular form, thedotted lines indicating the manner in which said tubular form is to beout to produce a set of arched sections, one of which is indicated bythe reference letter B. As will be seen, the blank B, which may be ofsheet metal, or of any desired sheet material, is arcuate in section,and as long as the desired diameter of the finished propeller. Thereterence character 7) is used to indicated the hole drilled in thepropeller to accommodate the engine shaft or any other motor with whichsaid propeller is adapted'to be associated.

The next step in effecting my improved. process is shown at C, whichindicates a onehalf section removed from each of the opmesses 'positeends of the blank B, back to a point adjacent the centre.

The reference letter 1) indicates in its full ous laminations cut asjust explained, and

superimposed with a hole 1) ready to accommodate the engine shaft or theshaft of a fan or blower, the dotted lines indicating the portionsremoved from the blank B.

In Fig. 2 the laminated propeller is shown in complete and assembledform, the blades L, L, and L being shown secured together by means ofthe hub H, comprising a pair of complementary arcuate hub flanges 1 and2 secured together in any desired manner as by bolts 3. The inner hubflange 2 is provided, either integral therewith or securedthereto in anydesired manner, with a cylindrical or othershape projection d toaccommodate the shaft S. The projection 4 may be tapered internally asshown to accommodate the end of the shaft S, and positioned thereon bymeans of the driving fit, or any other preferred securing means may besubstituted therefor. The end of the shaft 8 may be provided with asuitable nut to assist in holding the propeller in position.

lln Fig; 3 the laminations l, l, and l" are mounted precisely as shownin Fig. 2, but the propeller is adapted tor a reverse movement from thatshown in Fig. 2.

As will be seen from Fig. 2, the propeller in said figure has theattacking edges of each blade positioned in direct alignment, resemblingclosely the wood propeller of conventional type shown in Fig. 4, butdeviating therefrom in the design of the leading edges of each blade.

Of course the number of laminations used may be varied. and any numberfound in practice desirable may be employed; moreover, it is within theprovince of my invention to use other material than metal, tor example,the well known phenol condensation product called. bakelite or othermaterial may be substituted for either of these.

It is to be distinctly understood that it is also within the province ofmy invention to produce my novel form of propeller with till Mill

Birt

other shapes-than arcuate, for example, said 3 obvious that the same maybe modified throughout a Wide range. I therefore do not propose to belimited to the exact details of construction shown and described, butreserve the right in practice to make any and all modifications thereofthat fall within the scope of the appended claims.

I claim as my invention:

1. In a sheet metal propeller, in combination, an arcuate hub section,an arcuate blade integral with and extending from two sides of said hubsection. and sets of additional arcuate blade elements superposed onsaid blades, and extending a substantial distance along the length ofsaid blades.

2. In a sheet metal propeller, in combination, an arcuate hub section,an arcuate blade extending in offset relation from said-hub section,sets of arcuate blade elements superosed on said blades and adapted-toreinorce said blades. so that said propeller will be entirely free fromflat areas, and means sections and means for securing said hub sectionsand said flanges together, whereby said hub flanges and said hubsections may coact to form a true lock.

4. In apropeller. in combination, a set of superposed arcuated bladeelements of even thickness throughout and stepped both transversely andlongitudinally, and means associated with the mid-portion of saidelements for securing them together.

In testimony whereof I have signed my name to this specification.

JOSEPH A. BLONDIN.

